Lift planning apparatus

ABSTRACT

Lift planning apparatus for computing the required length, angular position, and free capacity of the boom of a crane apparatus, especially where the apparatus must work in a confined space. The apparatus of the invention includes a base scale calibrated into predetermined horizontal and vertical units related to distance; a protractor indicative of a crane; and a replica of a boom and a point section. The replica of the protractor, boom, and point section are arranged relative to the base scale so that various objects located within the area in which the actual crane is to work can likewise be scaled and placed onto the base scale thereby enabling one to ascertain by computation the optimum length and angular displacement of the boom. The apparatus further includes a replica of a jib having a point section slidably received thereon, with the jib being journaled to a second protractor, and with the second protractor being slidably captured along the replica of the boom, thereby enabling the optimum boom length and angular displacement, the optimum jib length and angular displacement, and the free lifting capacity at either of the point sections to be calculated.

United States Patent [191 Guffey 'et a1.

[5 LIFT PLANNING APPARATUS [76] Inventors: John W. Guffey, 306 HeadleeBldg,

Odessa, Tex. 79761; Richard D. Gillham, Box 2192, Odessa, Tex. 79760 22Filed: Oct.2, 1972 21 Appl.No.:294,357

[52] US. Cl 33/1 AA, 33/94, 116/124 F, 35/13 [51] Int. Cl B43l 7/06 [58]Field of Search 33/94, 98, 1 AA, 1 S, l B, 33/1 C; 35/13 [56] ReferencesCited UNITED STATES PATENTS 1,917,282 7/1933 Woodside 33/98 3,132,6275/1964 Lesatz 116/124 F FOREIGN PATENTS OR APPLICATIONS 135,646 12/1919Great Britain 33/76 VA Primary Examiner-William D. Martin, J r.Attorney, Agent, or Firm-Marcus L. Bates [57] ABSTRACT Lift planningapparatus for computing the required 1 July .23, 1974 length, angularposition, and free capacity of the boom of a crane apparatus, especiallywhere the apparatus must work in a confined space.

The apparatus of the invention includes a base scale calibrated intopredetermined horizontal and vertical units related to distance; aprotractor indicative of a crane; and a replica of a boom and a pointsection.

The replica of the protractor, boom, and point section are arrangedrelative to the base scale so that various objects located within thearea in which the actual crane is to work can likewise be scaled andplaced onto the base scale thereby enabling one to ascertain bycomputation the optimum length and angular displacement of the boom.

The apparatus further includes a replica of a jib having a point sectionslidably received thereon, with the jib being journaled to a secondprotractor, and with the second protractor being slidably captured alongthe replica of the boom, thereby enabling the optimum'boom length andangular displacement, the optimum jib length and angular displacement,and the 7 free lifting capacity at either of the point sections to becalculated.

7 Claims, 9 Drawing Figures PATENTEDJUL23IS74 llllllllll mnnrz 15 FIG. 1

' INDICATE GROUND LEVEL 05 UNIVERSAL CLEARANCE CALCULATOR Q LIFTPLANNING APPARATUS BACKGROUND OF THE INVENTION In erecting anddismantling structures such as large vessels, electrical motors,ventilation equipment, buildings and the like, especially where theconstruction is being carried out in a crowded area such as a complexpetro-chemical plant or the like, it is necessary to use a liftingdevice, such as a crane, in order to provide an overhanging structurefrom which an object can be lifted vertically and moved horizontallywhile clearing the surrounding structure.

Often a contractor will move his crane onto location in preparation forthe installation of a vessel, position the boom at its optimum anglerelative to the horizontal, and upon lifting the vessel with the pointsection of the boom discover that it will strike the boom beforesufficient vertical clearance is attained to enable swinging the vesselhorizontally into the new location. At other times a contractor willship his crane apparatus to the location, and after the job ofinstallation has commenced, discover that the improper boom length hasbeen employed for lifting a specified load a particular vertical height.

A jib is useful in reaching out to great radial distances from thecrane; however, in lifting loads with such a device, extreme cautionmust be taken to prevent overloading thestructure. When employing a jibfor lifting loads of significant weight many different complex factorsmust be considered, such as, for example: the free load capacity of theboom; the angular displacement of the boom; the attachment point of thejib relative to the boom; and the length and angular displacement of thejib relative to the boom. A jib usually is operated at or near maximumworking capacity and for this reason it is desirable that the length ofthe jib and theboom as well as the angular displacement of the jib andboom relative to one another and to the horizontal be placed at the mostadvantageous position relative to handling a maximum free load whilemaneuvering within the confines of a particular working area.

Heretofore, it has been common for the contractor to rely upon a trialand error solution to this perplexing problem which often requires manyhours of scaling and computation in order to arrive at a satisfactoryboom length, jib length, and the relative angle between the boom, jiband horizontal. Moreover, once the computations have been completed, notonly is it necessary to make absolutely certain that there is sufficientclearance for operating the crane, the boom, and the jib, but alsoassure that the load to be transported can be lifted a sufficientvertical height while maintaining an adequate radius of turn to clearall of the surrounding obstacles.

It would therefore be desirable to have made available a lift planningapparatus for computing the length, angular displacement, and freecapacity of a boom. Further, it would be advantageous to compute thesevariables for a boom having a jib attached thereto. It would bedesirable that such an apparatus be made available in a convenient formwhereby a scale model of the existing structure which is to berelocated, as well-as the surrounding structure within the working area,could all be assembled rapidly in more or-less graphic form to therebypositively endow the contractor with confidence in his infallibility tocompute all of the ramifications necessary to erect or dismantle vesselsand other objects in close working quarters.

SUMMARY OF THE INVENTION This invention comprehends a'lift planningapparatus in the form of a scaled model for computating the length,angular position, and free capacity of a boom. A base scale receives acrane protractor thereon which is indicative of a crane or the like, areplica of a boom is affixed to and depends from the protractor and hasa journaled end which enables the angular displacement relative to thereplica of the crane to be measured. A replica of a point-section isslidably received upon the replica of the boom and enables the optimumlength of the boom to be rapidly ascertained.

The invention further comprehends a second protractor slidably receivedlongitudinally on the replica of the boom. A jib replica is joumaled tothe protractor so that the angular displacement of the jib relative tothe boom can be determined rapidly. A second point section replica isslidably received longitudinally on the jib replica so as to rapidlydetermine the optimum length thereof.

The base scale preferably is of a material which can be cleaned ofgrease pencil, lead pencil, and the like, so as to enable either cutoutsor indicia representative of the surrounding structure to be removablyplaced thereon.

It is therefore a primary object of the present invention to providelift planning apparatus for computing the length, angular position, andfree capacity of a crane and boom combination.

Another object of the invention is to provide a lift planning apparatusfor computing the length and angular position of a boom and jib of acrane apparatus.

A further object of this invention is to provide apparatus for computingand planning the necessary crane apparatus to be employed in relocatinga structure.

A still further object of this invention is to disclose and provideimprovements in lift planning apparatus, related to crane apparatus,which include a protractor, and a replica of a boom and a point sectionall movable relative to one another and to a base scale.

Another and still further object is to provide lift planning apparatuswhich includes a protractor having a replica of a boom pivotallyattached thereto and a replica of a point-section slidably receivedthereon, and further including a jib protractor slidably received on theboom and having a replica of a jib pivotally attached thereto and onwhich there is slidably received a replica of a jib point sectionthereby enabling a work area or a specific scaled geographical locationto be reproduced in scaled relationship therewith.

An additional object of the present invention is to provide means bywhich the problems involved in moving structure with a crane apparatusmay be resolved by special scaled pictorial representations thereof.

These and various other objects and advantages of the invention willbecome readily apparent to those skilled in the art upon reading thefollowing detailed description and claims and by referring to theaccompanying drawings.

The above objects are attained in accordance with the present inventionby the provision of a combination of elements which are fabricated in amanner substantially as described in the above abstract and summary.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammaticalrepresentation of the present invention illustrated in one of itspractical working configurations;

FIG. 2 is an enlarged, broken, top plan view of a portion of theapparatus disclosed in FIG. -1;

FIG. 3 is an enlarged, fragmentary, top view of part of the apparatusdisclosed in FIG. 1;

FIG. 4 discloses part of the apparatus seen in FIGS. 1 and 2;

FIG. 5 is a cross-sectional view taken along line 55 of FIG. 3, but withthe apparatus being illustrated in a slightly different operatingconfigureation;

FIG. 6 is an enlarged, fragmentary representation of a portion of theapparatus disclosed in FIG. 1',

FIG. 7 is a cross-sectional view taken along line 77 of FIG. 6;

FIG. 8 is an enlarged fragmentary representation of part of theapparatus disclosed in FIG. 1; and

FIG. 9 is a cross-sectional view taken along line 9-9 of FIG. 8.

DETAILED DESCRIPTION OF THE EMBODIMENTS FIG. 1 discloses a lift planningapparatus for computing the length, angular position, and free capacityof a crane apparatus made in accordance with the present invention.

Throughout this disclosure the term crane relates to both stationary andmovable crane devices adapted to pivotally support a boom mounted injournaled relationship thereto. The term point-section relates toapparatus indicative of the removable portion of the free end of theboom which is located spaced apart from the pivoted end of the boom andhaving a sheave therein so as to enable a cable or the like to be roveabout a drum placed within the crane and stretched upwardly to thesheave, then vertically downward to a block, and then usually back up toa location in close proximity to the sheave located in thepoint-section. The term jib" relates to a secondary smaller boom whichusually is pivotally attached to an intermediate portion of the mainboom, and depends therefrom and generally includes a point-sectionassociated therewith having a sheave located therein in the beforedescribed manner. The term crane apparatus" is intended to include thecrane, booms, and point section.

The term base scale relates to a flat horizontal surface upon whichindicia has been placed with the indicia being related to scale of anactual crane, boom and jib apparatus. A replica of crane apparatus madein accordance with this invention can be slidably supported upon thebase scale in a manner similar to placing a book upon the top surface ofa desk or the like.

As seen in FIG. 1, a base scale 15 has a top surface formed into a planeupon which replicaof crane apparatus 16 is slidably supported. The basescale includes vertical and horizontal intersecting lines 17. Variousupstanding scaled structure 18, 19, and 20 have been included on thebase scale by either drawing the structure with a lead or grease pencil,or alternatively, by ac-- tually cutting the scaled structure from paperso as to enable it to be slidably and removably positioned as desired.

Numeral 21 and 121 indicates a replicia of a vessel which is to beeither removed from or installed into the illustrated position.Structure 21 and 121 preferably is a cutout made of paper, plastic, orthe like, so that the cutout can be moved relative to the base scale andto the scaled crane apparatus.

A crane protractor 22, indicative of a crane vehicle body, is indexedwith the arbitrarily choose-n ground level 23 so that pivot point atjournal 24 of the crane apparatus is arranged horizontally disposedabove the ground level in the same relative position that the actualcrane would be situated in its real environment.

The before mentioned journal 24 receives the journaled end of a replicaof a boom 25 therein so that the pivoted end 26 of the boom can bepivoted in a vertical plane about the journal as may be deemeddesirable.

A jib protractor 27 has a journal 28 formed thereon sothat the journaledend of a replica of a'jib 29 can be received thereon with the freedepending end 30 of the jib pivoting in a vertical plane about itsassociate journal. A replica of a boom point section 31 is superimposedupon the boom replica in a slidable manner so that the point section canbe arbitrarily'positioned anywhere along the longitudinal length of theboom.

It will be noted that spaced apart cables vertically depend from each ofthe point sections; however, in actual practice of the invention thepresence of these elements is not required.

In FIG. 2 there is seen the before mentioned replica boom having opposedparallel longitudinally extending edge portions 31, 31 equally spacedfrom center line 32. Parallel longitudinally extending spaced apartlines 132, 232 are sealed representations of booms of various widths andcapacity. Numeral 33 is an extension of center line 32 and forms apointer for use in conjunction with the before mentioned boomprotractor. Numeral 34 indicates the terminal end of the journaled endportion of the boom replica which is provided with a constant radius ofcurvature with the center thereof intersecting the journal 24.

In FIG. 3, numeral 35 indicates the upper face of the before mentionedboom protractor, which has indicia 36 provided thereon related to groundlevel so that the boom pivot point of the crane apparatus can be locatedabove ground level at a precise location which coincides with anydesired actual working model of a crane. Numeral 37' indicates indiciarelated to the 0 to of a protractor with the indicia being placedadjacent to the before mentioned pointer 33.

Fastener means 38 forms part of the before mentioned journal means.Spacer 39 underlays the upper plate member and provides reinforcement aswell as maintaining the entire scaled crane apparatus in proper alignedrelationship when it is supported on the base scale.

As seen in FIG. 5, in conjunction with FIGS. 3 and 4, the spacerincludes edge portions 40, 41 laying normal to one another and similaredge portions 42, 43

with edge portion 44 having a portion thereof formed with a radius ofcurvature which receives the curved end portion 34 of the boom closelyadjacent thereto so that the edge portions are slightly spaced apartasthey move relative to one another.

As seen in FIG. 5, the journal is comprised of a pin member having anenlargement in the form of a washer 45 which is reduced in diameter at46 so as to enable it to be received through the axially alignedapertures which are formed within the scaled boom and the boomprotractor. Washer 47 is affixed to the thimble in spaced opposedrelationship with respect to washer 45.

FIGS. 6 and 7 disclose the details of the jib replica and itsrelationship to the boom replica and attachment plate 27, also called ajib protractor. Formed on the attachment plate is indicia 49 related to0 to 90. The jib replica and protractor is indexed at 0 when the jib issuperimposed in parallel relationship with respect to the center line ofthe scaled boom. The jib replica includes a journaled end 50, a free end51, and spaced apart parallel sides 52, 53. The journal means includes afastener 54 formed along center line 55 with the jib protractor beingindexed with the scaled boom so that the vertical axial axis of thejournal means extends through centerline 32 of the scaled boom.

The jib protractor is provided with an upwardly directed plane or face27 which is provided with the before mentioned indicia, with a marginaledge portion'of the protractor being twice bent 90 so as to provide avertical edge portion 56 and a horizontal edge portion which terminatesat 57, thereby leaving a longitudinally extending groove within which amarginal edge portion 31 of the scaled boom is slidably captured in amanner to maintain the protractor properly indexed with the center lineof the scaled boom. Countersunk nut 59 threadedly receives the fastenermeans therein, although a hollow rivet or other type fastener meanscould be used in its stead.

FIG. 8 illustrates the details of the replica of the boom point section31. The point section is provided with means forming indiciaat 61, 62which is related to the physical size of the boom and which terminatesat point 132. Point 132 preferably terminates slightly short of theforward edge portion 63. Longitudinally extending opposed marginal edgeportions of the plate are provided with two 90 bends so as to provide avertical edge portion 64 and a horizontal edge portion 65 whichterminates in parallel spaced relationship with respect to similar edgeportion 65. thereby leaving opposed cavities 66 within which thelongitudinally extending parallel marginal edge portions of the scaledboom is slidably received. 1

Point section replica 67 is similar to point section replica 31 exceptfor size and for the indicia provided thereon. Point section 67 isslidably received upon the jib replicia in the same illustrated mannerof the before described boom point section replica.

OPERATION In operation, the base scale is laidout with the lines forminggrid 17 being spaced apart a sufficient amount to provide a scaleidentical to the scale of the various components of the crane apparatus,preferably with the horizontal and vertical grids extending 300 feet inscaled length while using a scale of one tenth inch/foot therebyrequiring a planar surface having a physical working area of 30 inchesby 30 inches. Ground level 23 is selected and the obstructions 18, 19,drawn or otherwise removably placed onto the base scale using a greasepencil, lead pencil, or paper cut-outs. Hence, the materials ofconstruction of the base scale preferably are of a plastic-like durablefinish which will admit of this practice.

The vessel 21 which is to be placed into the illustrated position ofFIG. 1 preferably is a cutout from a piece of paper so as to enable itto be moved freely about the board in any desirable mannerrepresentative of the actual contemplated working conditions to beencountered at the working area later on.

The boom protractor 22 is next placed relative to the ground level 23 sothat journal 38 is vertically positioned in the same relative verticalposition as the actual crane contemplated to be used. Theprotractor isnext slid horizontally into its contemplated working area upon the basescale.

The boom replica 25 is pivotally adjusted so that it clears all of theobstructions, and yet is at a reasonable angle for supporting theproposed hypothetical load therefrom. Jib replica 29 is next positionedat its optimum angle and the replica of the jib point section adjustedthereon so that the end thereof is axially aligned with the scaledvessel to be lifted and moved. Vessel 21, at this stage of theoperation, should be physically moved vertically upwards into proximityof the point section replica 67, and then the entire crane apparatusshould be movedhorizontally into the position where it is contemplatedthat the scaled vessel will be set down. This operation assures that thevarious angles and lengths of the boom and jib will be satisfactoryunder the existing working conditions. Next it is necessary to selectthe proper boom and jib sizes by refering to the boom and jib tables.One example of a boom table is as follows:

TON CRANE MAIN BOOM (loads in Pounds) Those skilled in the art willrealize that each particular crane and boom combination will require adifferent set of tables. In the above example, assuming the vessel 21weighs 5,500 pounds; that the jib is set 30 respective of the boom; thatthe jib is 60 feet in effective length; and that the boom is 150 feet ineffective length; that the angle of the boom provides a radius of feet;the following data can be selected from the table: the jib point sectiondescribes a radius of approximately 200 feet, and the main boom cancarry 9,000 pounds at a radius of 200 feet, and accordingly willadequately support a load of 5,500 pounds. However, the jib tableindicates that at 30 and 60 feet the jib will safely support a load ofonly 5,700 pounds.

It is therefore evident that extreme caution must be employed if theseselected values of the boom and jib are maintained because the entireapparatus will be working extremely close to its maximum workingcapacity. Those skilled in the art will realize that the above'dangerousselected configuration of the boom and jib could be alleviated by merelyselecting a different boom and jib length and perhaps by decreasing theangle of the jib relative to the boom. It is evident, having read theforegoing parts of this disclosure, that one could rapidly compute amore favorable configuration by repeating the above described procedure.

Where working conditions make it desirable to lift a scaled vessel 121from scaled point-section 131 of the replica of the boom, the presentinvention is invaluable in that it provides an actual working model ofthe conditions to be encountered upon location. In the example of FIG.1, when the cutout 121 is lifted vertically upwardly a sufficient amountto clear obstruction 20', it is evident that the top of the scaledvessel will strike the boom replica prior to being lifted a sufficientheight to clear obstruction 20'. For this reason it is necessary thatthe width of the actual boom to be used and any surrounding structure bescaled and furthermore herein lies one of the major teachings of thisinvention. To overcome this problem, it is elementary that a longer boommust be employed with the crane protractor being moved horizontallyfurther away from obstruction 20.

As a further example of the utility of the present invention, assumethat a vessel lOOfeet high and 12 feet in diameter is to be lifted onlythe amount required to move the vessel horizontally. Using line 232 ofboom replica 31 which represents a 90 ton boom, and positioning thescaled crane and boom adjacent to a scaled cut-out of the load, it isevident that a 150 foot boom length set at an angle to provide a 25 footradius is the minimum requirements for accomplishing the job. Thisprovides a boom angle of 82 to the horizontal which is undesirable, andaccordingly, employment of a longer boom which is disposed at a saferangle is desirable.

ln setting an air conditioning package on the top of a 60 foot roof,wherein the package weighs 1,200 pounds and must be disposed 50 feetfrom the nearest edge of the roof, it can be rapidly determined that a lfoot main boom with a 50 foot jib set will adequately handle andposition the load.

It is always desirable to determine the angle 37 of the boom relative tothe horizontal so that the crane operator can easily set his actual boomat the previously calculated angle, thereby taking full advantage of thepresent invention. Most cranes have a protractor provided thereon whichcan be used to accomplish this portion of the invention. I

The replica of the protractors, boom, jib, and point sections preferablyare made of clear plastic or plasticlike material so that the necessaryportions can be viewed through one another. For example, in theembodiment of FIG. 3, it is necessary that the protractor face 35 bemade of clear plastic material so as to enable arrow 33 to be viewedtherethrough. Should it be deemed desirable to make the protractor face35 of non-transparent material, it would be. necessary for boom to belocated in superimposed overlying relationship relative to theprotractor so as to enable a pointer, equivalent to pointer 33, to beproperly indexed with scale 37.

It is preferred to build the boom replica-of plastic, such as plexiglass(TM) so as to enable point 132 to be indexed easily with the scaleprovided on the replica of the boom and jib.

LII

Likewise, it is preferred that the second protractor be made oftransparent material so as to enable journal 54 to be indexed with theindicia placed on the scaled boom. It will be noted by those skilled inthe art that opposed longitudinally extending parallel lines 132 arescaled for a 45 ton crane, while lines 232 are scaled for a ton crane.The outermost edge portions of the scaled boom may be utilized as beinga scaled representation of still a larger boom. For example, using 1inch 8 feet, the boom width indicated by numeral 232 for a 90 ton craneapparatus would be approximately 1 inch in scale, that is, 8 feet inactual rectangular crosssectional area for crane equipment ofconventional design.

I claim:

1. Lift planning apparatus representative of crane apparatus forcomputing the length, angular position, and free capacity of a boomcomprising:

a base scale, means by which said base scale is calibrated intohorizontal and vertical units related to distance;

a crane protractor indicative of a crane; an elongated boom replica, aboom point section replica;

said boom replica having a free end and an opposed journaled end, meansby which said journaled end is affixed to said crane protractor, meansby which said point section replica is slidably received in indexedrelationship respective of said boom replica;

means by which said crane protractor, boom replica,

and boom point section replica are slidably supported for movement onsaid base scale; said boom replica having means thereon cooperative withsaid protractor for determining the angle said boom replica is displacedfrom the horizontal; said boom replica having means forming indiciathereon forming a scale related to the width and length thereof withsaid scale being calibrated into said units; whereby;

said crane protractor and boom replica can be laid on said base scalealong with scaled means representative of the area in which the workingcrane apparatus is to be used, and the optimum length and angle of theboom for achieving a predetermined free load capacity can be computed.

2. The lift planning apparatus of claim 1, and further including a jibprotractor slidably received on said boom replica, an elongated jibreplica having a free end and a journaled end, means by which saidjournaled end is journaled to said jib protractor; and, a jib pointsection replica slidably received on said jib replica;

whereby: said length and angle of said jib replica can be computed bypivoting the jib replica into a desired position for lifting, and notingits angular relationship relative to the boom replica on the jibprotractor.

3. The lift apparatus of claim 2 wherein said crane protractor isprovided with indicia related to 90 of are, said indicia being arrangedrelative to a portion of said boom replica so that a portion of saidboom is indexed with said indicia to indicate the relative angularposition of the boom replica relative to the horizon;

said jib protractor being provided with indicia related to 90 of arc,said indicia being arranged relative to the boom and jib replica toindicate the relative angle therebetween.

4. The lift apparatus of claim 1 wherein said crane protractor isprovided with indicia related to 90 of arc, said indicia being arrangedrelative to a portion of said boom replica so that a portion of saidboom replica is indexed with said indicia to indicate the relativeangular position of the boom replica relative to the horizon;

said jib protractor being provided with indicia related to 90 of arc,said indicia being arranged relative to the boom and jib replica toindicate the relative angle therebetween.

5. The lift apparatus of claim 1 wherein said crane protractor has aflat surface area defined by edge portions, a reinforcement underlyingsaid flat surface with an edge portion of said reinforcement beingconcave in form; said boom replica underlying said flat surface andhaving a curved end portion received within said concavity, with thelower face of said reinforcement forming a support means for said boomreplica and said crane protractor.

6. The lift apparatus of claim 1 wherein said jib protractor includes acavity within which the boom replica is slidably received; said jibreplica being journaled to said jib protractor with said journal beingaligned with p replica therein, respectively.

1. Lift planning apparatus representative of crane apparatus forcomputing the length, angular position, and free capacity of a boomcomprising: a base scale, means by which said base scale is calibratedinto horizontal and vertical units related to distance; a craneprotractor indicative of a crane; an elongated boom replica, a boompoint section replica; said boom replica having a free end and anopposed journaled end, means by which said journaled end is affixed tosaid crane protractor, means by which said point section replica isslidably received in indexed relationship respective of said boomreplica; means by which said crane protractor, boom replica, and boompoint section replica are slidably supported for movement on said basescale; said boom replica having means thereon cooperative with saidprotractor for determining the angle said boom replica is displaced fromthe horizontal; said boom replica having means forming indicia thereonforming a scale related to the width and length thereof with said scalebeing calibrated into said units; whereby; said crane protractor andboom replica can be laid on said base scale along with scaled meansrepresentative of the area in which the working crane apparatus is to beused, and the optimum length and angle of the boom for achieving apredetermined free load capacity can be computed.
 2. The lift planningapparatus of claim 1, and further including a jib protractor slidablyreceived on said boom replica, an elongated jib replica having a freeend and a journaled end, means by which said journaled end is journaledto said jib protractor; and, a jib point section replica slidablyreceived on said jib replica; whereby: said length and angle of said jibreplica can be computed by pivoting the jib replica into a desiredposition for lifting, and noting its angular relAtionship relative tothe boom replica on the jib protractor.
 3. The lift apparatus of claim 2wherein said crane protractor is provided with indicia related to 90* ofarc, said indicia being arranged relative to a portion of said boomreplica so that a portion of said boom is indexed with said indicia toindicate the relative angular position of the boom replica relative tothe horizon; said jib protractor being provided with indicia related to90* of arc, said indicia being arranged relative to the boom and jibreplica to indicate the relative angle therebetween.
 4. The liftapparatus of claim 1 wherein said crane protractor is provided withindicia related to 90* of arc, said indicia being arranged relative to aportion of said boom replica so that a portion of said boom replica isindexed with said indicia to indicate the relative angular position ofthe boom replica relative to the horizon; said jib protractor beingprovided with indicia related to 90* of arc, said indicia being arrangedrelative to the boom and jib replica to indicate the relative angletherebetween.
 5. The lift apparatus of claim 1 wherein said craneprotractor has a flat surface area defined by edge portions, areinforcement underlying said flat surface with an edge portion of saidreinforcement being concave in form; said boom replica underlying saidflat surface and having a curved end portion received within saidconcavity, with the lower face of said reinforcement forming a supportmeans for said boom replica and said crane protractor.
 6. The liftapparatus of claim 1 wherein said jib protractor includes a cavitywithin which the boom replica is slidably received; said jib replicabeing journaled to said jib protractor with said journal being alignedwith the longitudinally extending center line of said boom and said jibreplica.
 7. The lift apparatus of claim 1 wherein said jib and boompoint section replicas are each made of transparent material, indiciaformed on the material related to a sheave, opposed cavities formed ineach said point sections respectively, for receiving said jib and boomreplica therein, respectively.